1. Field of the Invention
This invention relates in general to a motor vehicle type engine, and more particularly, to a means for balancing engine vibrations.
It is a primary object of the invention to provide a desmodromic device that will balance second order engine vibrations; i.e., those vibrations that are caused by second order vertical shake as the pistons move radially, by means of a crankshaft-driven vibration balancing mass that is oscillated by contoured cams attached to the crankshaft and engaging low friction cam follower rollers or sliding shoes pivotally secured to a balancing mass.
The invention, therefore, is directed to a force driven balancing mass in contrast to a vibration driven balancing device that would cause the engine to be less responsive to vibrations rather than cancelling or balancing them out in the manner of this invention.
2. Description of the Prior Art
Crankshaft-driven vibration balancing devices are known. For example, Sampietro, U.S. Pat. No. 3,468,190, shows a vibration balancing mass consisting of a piston secured to a shaft having wheels or rollers at its opposite ends engageable with contoured cams on the cheeks of the crankshaft. Reciprocation of the piston balances secondary shake forces.
Ljungstrom, U.S. Pat. No. 2,235,160, shows a vibration balancer member 44 slidable vertically or radially with respect to the crankshaft in a direction directly opposite to the direction of piston travel. The mass and acceleration of the balancer are matched to those of the piston to generate forces equal and opposite to both the first and second order acceleration forces of the piston. To effectively balance the second order vertical shake of an I-4 engine, four of these balancer members would be required, one to oppose each of the engine's four pistons, which is quite different from the inventin to be described.
Research disclosure of May, 1982, No. 21731, "Reciprocating Balancer (F06)", shows an engine block having a reciprocating frame mounted on rollers on which are mounted elliptical gears engageable with a gear on the crankshaft to cause oscillation of the frame to balance undesirable engine vibrations.
Thauer et al., Offenlegungsschrift No. 23 33 038, shows a dual cam arrangement secured to the crankshaft for actuating a balancing mass that is arcuately pivotally secured to a part of the frame and movable to balance undesirable engine vibrations.
Wise, U.S. Pat. No. 1,640,634, shows a cam mounted on the crankshaft with two cam lobes for actuating a lever 36 that is attached to a reciprocating plunger for balancing engine vibrations.
It is a primary object of the invention to provide a desmodromic type vibration balancing mass that will not only cancel out undesirable engine vibrations, but will do so with a minimum of friction; this being accomplished by providing the device with low friction cam follower means.
The above prior art does not teach or describe such a construction. None of the above prior art shows or describes any means for reducing friction during oscillation of the vibration balancing mass.